Recording tachometer



Jan. 26, 1937. u. KOHLER 2,069,152

RECORDING TACHOMETER Filed Jan. 51, 1953 2 Sheets-Sheet 1 U. KOHLERRECORDING TACHOMETER 2 Sheets-Sheet 2 Filed Jan. 31, 1955 luuuum TIEJan. 26, 1937.

a .1 d \WNGQ 4 a q, .M a P fl Patented .Ian. 26, 1937 PATENT. OFFICERECORDING TACHOMETEB I Ulrich Kohler, Bern, Switzerland, assig'nor toHauler A.-G. vormais Telegraphenwerkstfitte von G. Hasler, Bern,Switzerland Application January 31, 1933, Serial No. 654,534 r InSwitzerland February 23, 1932 8 Claims.

' time, by clockwork, while the vehicle is stationary, and wherein astylus for recording the time is moved across the strip at regular timeintervals.

I Heretofore for recording the hours of the day, either a separatestylus was brought into operation at predetermined points on the strip,or else a time-recording stylus was reciprocated in rapid succession anumber of times which corresponded to the hour of the day. In bothcases, however, it was difllcult to read the time of day from the str p.

The present invention has for one of its objects the provision of animproved construction of tachometer of the described kind in which thisdifllculty is avoided, and in which the time of day can be readily readfrom the record strip.

According to the invention, a recording tachometer is provided of thekind described,

wherein the stylus is reciprocated several times within the given timeunit of say one hour, and

the points of the time record which are coincident with the hours areindicated by a type wheel or disc that records the hour numerically, sothat they can be read without difiiculty.

0 Conveniently, the types of the wheel are formed by points whichperforate the strip for recording the hours.

j According to a feature of the invention, the type wheel is rotated bythe clockwork by means of a worm and a crown wheel fixed to the typewheel, and for recording the hours on the strip, the type wheel is movedforwards and backwards in quick succession at right-angles to the strip,by a striking mechanism controlled by the clockwork. r

In a preferred construction, an eccentric forming part of the clockworkcontrols the locking lever of an escapement the detent of which canrotate approximately one revolution, and at the same time serves as thecontrol member of a lever which effects the to-and-fro movement of thetype wheel by means of a connecting rod.

Conveniently, the escapement mechanism constitutes the locking device ofthe spring-barrel axle of the clockwork, for which purpose a one-wayclutch is interposed between. the said axle and the detent.

According to another feature of the invention, the lever controlled bythe detent of the escapement mechanism is connected by a spring with asecond lever which is so influenced by a cam rotating with the detentthat the spring is subjected to an increased tension for feeding thetype wheel against the strip. a

One embodiment of the invention is diagram- 5 matically illustrated byway of example in the accompanying drawings, wherein:

7 Figure 1 is a sectional side elevation of one form of tachometeraccording to the invention,

Figure 2 is a plan view thereof,

Figure 3 is a diagram,

Fig. 4 is in part a section in the vertical longitudinal plane of axisi1, and in part an elevation viewed from the left of Fig. 1, parts 21and 3|-38 being omitted for the sake of clarity,

Fig. 5 is an elevation taken from the right side of Fig. 1; and

Fig. 6 is a section on line 6-8 of Fig. 1, the spring cases 3 and 4being omitted, and

Figures '7 and 8 are detail views described herego inafter.

Like reference characters designate like parts in all the views.

' Referring to the drawings, between the front plate I and the verticalpartition wall or plate 2 5 two spring barrels 3 and 4 (Figs. 2 and 5)are arranged on an axle common to both of them. The springs therein worktogether, i. e. they are coupled in known manner so that both can bewound up simultaneously and both will run down 30 together. The doublespiral spring housing is employed in order to provide a sufllcientlylong operation of the drive mechanism. The spiral springenclosed by thebarrel 3 (Fig. 2). acts at its inner end on the spring barrel shaft,which 'carries along or drives the wheel Ill, through which the drivefor the reciprocal movement of the marking wheel 53 is actuated. Thetoothed rim 5 of the barrel 4 meshes with a pinion 6 which is free torotate on an axle I which rotates once in 40 an hour and whichhereinafter is called an hour axle, and which pinion fixedly carries aspur gear 8 which cooperates with the escapement, not shown, of theclockwork. The pinion 6 drives a spur gear ll fast on the hour axle I,by means of a coil spring 9 and a friction disc III, the said gear wheelll meshing with two pinions i2 and IS. The paper advance roll 35 isdriven from the shaft (not shown) of the speedometer by means of theratchet wheel 80, which may be fast. on the said shaft, in which wheel80 a pawl engages resiliently, said pawl being mounted on gear 82, looseon the same shaft as wheel 80, which gear drives the gear 40 of theadvance roller 35 in one direction only. The shaft of the ratchet wheel80 is driven from the shaft of the speedometer in suitable manner andwhen the wheel 80 is being rotated, it will drive the paper feed roller35 through the intermediary of the pawl 8| and gear However, when thespeedometer shaft is at rest and the roller 35 derives its motion fromthe shaft I, the said roller, travelling in but one direction, carrieswith it the loose gear 82 and the pawl 8|, so that the latter passesidly over the teeth of the ratchet wheel 80. The shaft I4 of the pinionI3 carries in front of the plate a knob I5 for setting the clockwork.The ratio of the number of teeth of the pinions II and I2 is 3:1

so that during each revolution of the hour axle I, i. e. every hour, thepinion I2 and a worm I6 Within a.casing |8 attached to the front plate Ia shaft I'I carries a crank arm I9 whose pin engages one end of a link2I., The other end of this link 2| carries a pin 25, one end of which isguided in a stationary cam groove 22 and the other end is movable in ahorizontal slot 23 of a vertically movable rod 24 which carries arecording or marking member 26 (Fig. 4), hereinafter referred to as astylus. Figs. 1 and 2 show that one end of pin 25 engages in theellipsoidal groove 22 of the vertical plate 22, while the other endengages in the horizontal slot 23 of the vertically slidable support 24of pencil 26. The details of the mechanism for tracing curves on paperstrip 21 and the drive therefor have nothing to do with this invention,which relates to the mechanism for indicating the hours on the paperstrip. This stylus is uniformly moved, once up and once down, in twentyminutes, this action being brought about by-the described crankmechanism. The stylus thus reciprocates three times an hour. The timecu'rve'28 shown at the left hand in Figure 3 is made by the stylus 26 onthe paper strip 21 which is fed past it. The speedcurve 29 is made by arecording member 29' shown in Fig. 1.

Feed of the record strip The paper strip 21 is fed by the devicedescribed below during the movement of the vehicle carrying thetachometer, whether forwards 50 or backwards, the strip always moving inthe same direction and in an amount proportional to the distancetraversed. When the vehicle is stationary, the strip is moved accordingto time by clockwork. The strip extends horizontally 55 from asupplyroll 30'entire1y across the width of an abutment plate 3| oppositethe stylus 26, around vertical guide rollers 32 and 33, and between twovertical feed rolls 34 and 35, to a. takeup roll 36 (see Fig. 6, alsoFig. 2). The feed 60 roll 34 at both ends has peripheral recesses 31(Fig. 5) and the roll has driving pins or teeth 38 adapted to engagethese recesses, so that the strip will be positively fed according tothe distance traveled, or else exactly according to the 65 elapsed time.

The feed roll 35 carries a gear wheel 40 (Figs. 2 and 5) which mesheswith a pinion 39. The distance shaft, not shown, of the tachometer isoperatively connected with the wheel 40. ,The 0 pinion' 39 is connectedby means of a. larger wheel 4| with a gear wheel 42 mounted on. avertical shaft 43 and is rigidly connected with a ratchet wheel 44. Aspring 45 (Figure 7} formed at one end as a pawl, engages the ratchetwheel 75 44, its other end being attached to a cup-shaped 2,069,152 Idisc 46 which encloses the ratchet wheel,

The disc 46 is firmly connected to a bevel wheel 41 which meshes with abevel pinion 48 fast on the hour axle 1. The particular drive of thepaper strip during travel and on standstill is old per se'and does notform part'of the in-' of whether the vehicle is moving. During thistravel of shaft I the shift pawl 45 between the wheel 45 and the wheel44 (Fig, 7) simply slides over and off the teeth of the more rapidlyrotating wheel 44, while when the vehicle is at a standstill it carriesthe wheel along and thus drives the paper strip according to time. Sucha drive is described and shown in German Pat. 388,828, to Reszny.

In order that when setting the clock by tuming the axle I backwards byhand, the paper strip 21 will be fed in the same direction as. when thehour axle I rotates in the normal direction,

the bevel pinion 48 on the hour axle I meshes with a bevel wheel 49disposed above it and firmly secured to a disc 50 which, like the disc46, controls a ratchet wheel 5| by aspring pawl, not shown. This disc 50imparts a movement to the ratchet wheel 5| which is,in the oppositedirection of rotation to that of the ratchet wheel 44, the said ratchetwheel 5| being fast on the shaft 43. By turning the knob l5 and the houraxle I in the one or other direction,the shaft 43 together with therolls 35 and 34 will always be moved forwards either by the lowercoupling 44, 45, 46 or by the upper coupling 5|), 5|.

Recording hours at the time curve is guided by a pin movable in atransverse -member 56, while its right hand end is pivoted to a lever58(see also Fig. 5) On the periphery of the wheel 53 are providednumbers ranging from 1 to 24 corresponding to the twenty-four hours of aday, and the wheel rotates once in twenty-four hours. The numbers whichconstitute types, are formed by very fine points arranged in groups.each in the form of a numeral, so that the numbers can be perforated inthe strip when the type wheel 53 is pressed by the rod 51 against thestrip. A roller 59, covered with hard felt or the like, arranged on itsaxle beside the upper endof the roller 32 serves as an abutment for thepaper strip at that side of the latter which is opposite the type wheel.

The lever 58 is shown as rotatable on a pivot 60 of a tensioning lever52, which in turn, is fulcrumed at 6|. Suitable means such as a spring63 pulls this lever 58 to the left in Fig. 1, towards the lever 62. Now,when the roller I9, disposed on that end of the lever 62 which isattached to the spring 63, is caused to slide down from the apex of thecam 80, on which it bears, due to the rotation of the said cam, thenthelever 58 cam and also the rotation of the shaft 14 (Fig. 8) on which thecam 88 is mounted. To prevent such contact between the lever 58 and thecam 80, a

' pin 62' (Fig. 1) is provided on the lever 62 in staggered relativelyto one another both radially and in the direction of rotation of thecam, and extend into the range of the bent lower end of 2.

- lever 69 fulcrumed at 68 (Fig. 1); this lever 69 of the gear wheel I3.

normally prevents the rotation of the cam 65 by a train of gears I0, II, 12, I3 driven by the springbarrel axle (Fig. 2) through a dog clutch15 which is arranged on the axle I4 of the cam 65 and is operative inonly one direction. A coil spring 16 encircling the axle tends, to holdthe dog clutch I5 engaged, one of the parts of which is formed by a hubof the cam 65, and the other by a hub The cam 65 together with the lever69 forms the escapement for the springbarrel axle. The dog clutch I5permits the main springs to be wound up by turning the springbarrel axlewithout turning the cam 65 backwards.

The escapement 65, 89 is controlled by a fork 11 (Fig. 1) which isrigidly connected with the lever 69 and embraces an eccentric I8 fast onthe hour axle I. The hub of the cam 65 carries'a cam 88 that lies withinrange of an anti-friction roller I9 of the lever 62, by which cam 80 thetension of the spring 63 is increased for approximately one revolution(time of escapement) a pinion 6 mounted freely on the shaft I, which'revolves once every twenty-four hours.

is rotated once each hour, by virtue of the regulatory action of a spurgear 8 fast to the pinion 6,

and which cooperates with an escapement (not shown) for controlling theclockwork mechanism. Through the intermediary of the coiled spring 9 andthe friction disc [0, the gearwheel II meshes with the two pinions I2and I3. The shaft of the pinion i3 carries the knurled knob [5 whichprotrudes exteriorly of the casing for setting the clockwork and formanual adjustment. The pinion I2 is fast to the worm l6, and the ratioof the teeth of the gear wheel II to those of the pinion i2 is 3:1, sothat for each revolution of the hour shaft I, the pinion l2 revolvesthree times, i. c. it makes a complete revolution every twenty minutes.

As shown in Fig. 4, the worm l6 meshes with the crown wheel 52, whichin'turn is fast to the 'type wheel 53, carrying numbers 1-24 inclusive,

the gear ratio being such that the said type wheel Thus, every hour oneof the 24 numbers on the type wheel is brought, in rotation, intooperable position.

Since the crank I8 is fast to the shaft II on which the pinion I2 andworm I6 are mounted,

it is moved completely over the oval guide 22 (Fig. 1) every twentyminutes, and since the pin 25 engages the slotted head 23 of thevertically movable rod 24, the stylus 26 is reciprocated three times perhour, thereby tracing the time record 28,

shown in Fig. 3.

The means for reciprocating the type wheel, together with the crown gear52, will be explained hereinafter.

Next, it becomes necessary to explain the means for moving the timechart continuously in a single direction. As will be recalled, and as isevident from Figs. 2 and 6, the time chart is moved by means of thedriving cylinder 35, cooperating with the driven cylinder 34 in suchmanner that the record strip 21 is unwound from the supply roll Ill andis then moved across guide rollers 58, 32,'and 33, to the rolls 34 and35, and thence to the takeup roll 36. Suitable gearing, not shown,serves to drive the take-up ,roll 38 from the drive roll- 85.

As shown in Figs. 2 and 5, the bevel pinion 48 is fast to the hour shaftI, and meshes continuously and 50, respectively controlling ratchetwheels 44' and SI by means of corresponding pawl springs such as areshown at 45 in Fig. '7. The bevel pinion 48 acts on one or the other ofthe .bevel wheels 46 and '48 only when the vehicl'elis at a standstill,and the. paper strip is being driven by the clockwork. During travel,this shaft 43 is turned by the gear 40 from the motor drive shaft morerapidly than the wheels 46 or 48 are driven when the vehicle is at astandstill. As stated in the foregoing, the time shaft I turnscontinuously, and during the movement of the vehicle, the pawl 45 simplyslides over and off the teeth of the more rapidly rotating wheel 44,while when the vehicle is at a standstill, the pawl carries the wheelalong and thus drives the paper strip according to time. The action isof the differential type.

Now, it will be seen that it is essential that the paper strip be movedconstantly in a single direction, regardless of whether the clockworkadjustingmember I5 is turned in either a clockwise or acounter-clockwise directiomand it is to this end that the differentialgearing is employed. Thus, by turning the knob I5 and hence the houraxle I in either direction, the shaft 43 together with the rolls "35 and34 will. always be moved in the proper direction, either by the lowercoupling 44, 45, and 46 or by the upper coupling 49, 50, and. 5|.

Next, it will be described the means for reciprocating the type wheel,and in this connec- "tion, attention is to be directed primarily to Fig.1,

but also, to a lesser extent, tongs. 2-, 5, 6, and 8. As shown in Fig.1, the eccentric I8 is fast to the hour shaft 1 and rotates therewithonce each hour. A forked arm 11 embraces the said eccentric and ispivoted at 68, being fast to the -.lever 69, which,.as best shown inFigs. 1 and 8, terminates in a bent, bevelled portion. at its free end.

I fast to the gear wheel I2, in turn meshing with iii the pinion 13 onthe shaft 14, in the manner of a train of stepup gearing. Secured to theshaft I4 is the cam 65, having pins 66 and 6'1 as described previously.Now, the tendency of the pinion 13 is to rotate this cam 65continuously, but the engagement of the free end of the lever 69 withthe pins 66 and 61 prevents this. The eccentric 18 rocks the lever 69once every hour, and during the first portion of the movement of thislever 69, i. e. immediately after the type wheel .53 has made an imprinton the time strip 27, the lever 69 engages at its free end the pin Sland holds the cam 65 against rotation. In the next subsequent course ofthe revolution of the eccentric 18, the lever 69 is caused to releasethe pin 6l, so that under the actuation of the clockwork mechanismthrough the said train of gearing, the cam 65 is quickly flippedthroughapproximately 30 degrees until the lever 69 engages the pin 66.During turning of the cam 65, the cam 80, fast to the same shaft 14 onwhich the cam 65 is mounted, is also turned, and by reason of thecontact of its humped portion with the roller it! on the lever 62 this'lever is forced outwardly, i. e. to the left in Fig. 1. At the sametime the lateral lug 64 on the lever 58 engages the hump of the cam 65and is pushed to the right in Fig. 1, thereby tensioning the spring'63.

In the next phase of the rotation of the eccentric E6, the lever 69 iscaused to slip ofi the pin 66, so that the train of gearing quicklyflipsthe cams 65 and 80 through approximately 330 whereby the-lug 64 isreleased from the hump or the cam 65. This permits the tensioned spring63 to contact forcefully, pivoting the lever 58 about its pivot point89, and striking with its type wheel 53 against the abutment Immediatelythereafter the roller i9 slides off the hump por-- tion oi the cam iii?thereby lessening the tension on the spring 53, and thus reversing theload on the earn 55 as it withdraws the type wheel 53 from itsimpressing position. By the engagement 01" the crown wheel 52 with theworm i 6 in the manner previously described the type wheel 53 haspreviously been rotated g gth of a revolution, so that the proper hourdesignation is brought into position.

The dog clutch it, previously described, and the spring it are simply tofacilitate rewinding oi the clockwork mechanism in any suitable manner,inasmuch as these clutch elements ensure uni-directional movement ofthe'cams and hence of the shaft Mandthus of the earns 65 and 86 The nextthing for consideration is the chart of Fig.2. The stylus 26 traces thetime record 28;

and considering the top portion thereof, from numerals' 3 and 5,representing the lapse of one hour, the stylus will have beenreciprocated three complete cycles. I The length of the charge coveredby the path of this tracing-is dependent, not on the clockworkmechanism, but on the speed at which the vehicle travels, the drive nowbeing by. the vehicle-driven pawl 40. This is evident from the speedcurve 29, traced by the stylus 29'. Now, at 28' is shown the time recordwhich is traced when the vehicle is at a standstill, i. e., when thepaper strip is fed by a clock-mechanism. Correspondlngly, the tracing 29shows a similar interval;

. 26 is moved up and down and the hours are marked by thetype wheel 53.It may happen that the clock is moved backwards instead of forwards.This can be'seen from the curve 28 in Figure 3. When the vehicle isstationary, the curve drawn by pencil 26 consists of a uniform zigzagline of small extent for a comparatively long period of time; see 'curve28 in the middle of Fig; 3. When the vehicle is in motion, i. e. whenthe strip advances according to the speed, the zigzag line is more orless drawn out or extended; see curve 28'at the top and bottom of Fig.3. Since pencil 25 (Figs. 1, 4, and 6) is constantly moved upwardly anddownwardly uniformly, once up and once down in 20 minutes, this timeline includes six directional changes per hour at intervals of tenminutes. Thus the third node 28 upwardly beyond 3 in curve 28 represents3X or 30 minutes past 3; i. e. 3:30. Curve 28 is therefore a time linewhich makes it possible to read the speed of the vehicle at any minuteon the speed curve 29. The paper strip is provided only withlongitudinally extending lines, which cannot be seen on the drawings,for indicating the speeds I shown on line 29. Time curve 28, in Fig. 3,shows that the vehicle stopped shortly before 6 oclock in the evening(iii). The speedometer clock stopped at 5 oclock in the morning of thenext day. Of course, the paper strip also stopped moving. The next timethe vehicle was started at 3 oclock in the morning. It was firstnecessary to turn the clock of the speedometer which stopped at fiveo'clock, back to three o'clock. That is, the clock was set back twohours, and this is indicated by the fact that numerals 4 and 3 follownumeral 5 in the constricted zigzag line, and after starting of thevehicle the numeral i follows the numeral 3, there being an elongatedzigzag line to indicate that the paper strip is now being driven by thevehicle. Had the driver moved the clock forward, the numerals 5, 6, 7 to24 and then 1 to 3 would appear in the form of a constricted zigzag lineon the paper strip. However,

'by turning back the clock from 5 to 3, the driver saves work, time andextent of paper strip. Suitable legends on the chart of Fig. 3 indicatethe meanings of the jogs in the speed curve.

senting hours, means for rotating said wheel by a clock-driven axle, andmeans for bringing said wheel into and out of marking relation with therecord member at the end of each time unit.

2. In a recording tachometer for a vehicle having a feed mechanismfor'feeding a continuous record strip, means for actuating said feedmechanism according to distance while the vehicle is moving, and aspring-driven axle for actuating said feed mechanism according to timewhen the vehicle is stationary; a stylus mounted to move across therecord member, means driven by said time axle for reciprocating thestylus repeatedly during a unit time, a wheel having type numeralsrepresenting hours, means driven by said time axle for rotating saidwheel, and means for moving said wheel against the record member andmarking the latter at the end of each time unit.

3. In a recording tachometer for a vehicle having a feed mechanism forfeeding a contmuous record strip, means for actuating said feedmechanism according to distance while the vehicle is moving, and aspring-driven axle for actuating said feed-mechanism according to timewhen the vehicle is stationary; a stylus mounted to move transversely ofsaid strip, means driven by said time axle for reciprocating the stylusrepeatedly during a unit time, a type wheel having peripheral typenumerals, a crown wheel fixed to said type wheel, a worm wheel driven bysaid time axle and meshing with said crown wheel, and striking mechanismcontrolled by said time axle and arranged to move the type wheelforwards against the strip and backwards away therefrom in quicksuccession in a direction substantially. normal to transversely of saidstrip, means driven by the time axle for reciprocating the stylusrepeatedly during a unit time, a type wheel having peripheral typenumerals, means driven by said time axle forrotating said type wheel,and reciprocatory mechanism for reciprocating said type wheel towardsand away from the strip, said reciprocatory mechanism comprising aneccentric driven by said time axle, a connecting rod having one endrotatably connected to the type wheel at its axis of rotation, aspring-controlled lever connected to the other end of said connectingrod, an escape.- ment device comprising a detent rotatable throughapproximately 360 and controlling said lever, and a locking levercontrolled by said eccentric and controlling said escapement device.

5. In a recording tachometer tor a vehicle having a feed mechanism forfeeding a continuous record strip, means for actuating said feedmechanism according to distance while the vehicle is moving, and aclockwork mechanism for actuating said feed mechanism according to'timewhen the vehicle is stationary; said feed mechanism comprising a timeaxle, a stylus-mounted to move transversely of said strip, means drivenby the time axle tor reciprocating the stylus repeatedly during a unittime, a type wheel having peripheral type numerals, means driven by thetime axle for rotating said type wheel, a spring-driven axle, a barrelrotatable on the latter axle and geared to the time axle, a springconnected at one end to the spring'driven axle and at its other end tothe barrel, and reciprocatory mechanism, for

. record strip means for actuating said feed mechanism according todistance while the vehicle is moving, and a spring-driven axle foractuating said feed-mechanism according to time when the vehicle isstationary; a stylus mounted to move transversely of said strip, meansdriven by the time axle for reciprocating the stylus repeatedly during aunit time, a type wheel having peripheral type numerals, means driven bysaid time axle for rotating said type wheel, and reciprocatory mechanismfor reciprocating said type wheel towards and away from the strip, saidreciprocatory mechanism comprising an eccentric driven by said timeaxle, a. connecting rod having one end rotatably connected to the typewheel at its axis,

a lever connected to the other end of said connecting rod, an escapementdevice comprising a detent rotatable through approximately 360 andcontrolling said lever, a locking lever controlled by said eccentric andcontrolling said escapement device, a second lever on which thefirst-mentioned lever is fulcrumed, a tension spring connecting saidlevers together, and a cam rotatable with said detent and disposed tosubject said tension spring to increased tension for moving the typewheelagainst the strip. I

7. In a recording tachometer, in combination, a clockwork mechanism, apaper strip, means connected with said clockwork mechanism for movingsaid-paper strip, a wheel having time figures on its periphery, a stylusmovable transversely of said strip for tracing a time record on saidstrip during passage of the latter, means .energized by said clockworkmechanism for reciprocating said stylus across said strip, and meansalso driven by said clockwork mechanism for moving said wheel into andout of contact with said strip, and for rotating said wheel step by stepabout its axis after each contact of the wheel with the said strip.

8. In a recording tachometer for a vehicle having a feed mechanism forfeeding a paper record strip, means for actuating said feed mechanismaccording to distance while the vehicle is moving, and a clockworkmechanism for actuating said feed mechanism according to time when thevehicle is stationary; a numeral printing device,

a recording pencil, means for reciprocating 'said pencil several timesan hour across said strip in order to produce a time line thereon, saidnumeral printingv device consisting of a perforating type wheel forindicating the hours of the day along the time line of the strip in theform of periorated numerals, a worm and a meshing crown wheel driven bysaid clockwork mechanism for rotating said type wheel, a cam axle, a dogclutch connecting said axle with said clockwork mechanism, said dogclutch-being operable in but one direction of rotation, a checkingdevice permit- .ting a momentary substantially complete revolution ofthe cam check, and a lever controlled by said checking device, saidlever being connected with the support of the type wheel, a second leverinterconnecting said levers, and a cam on said cam shaft rotatable withthe check member for actuating said second lever, said second leverbeing adapted to tension said spring for pressing the type wheel againstthe paper strip in rapid reciprocai movement.

ULRICH xomm

